Electrical Work Safety Program - TWU Home · o 29 CFR 1910.333 – Selection and Use of Work...
Transcript of Electrical Work Safety Program - TWU Home · o 29 CFR 1910.333 – Selection and Use of Work...
To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/
Electrical Work Safety Program
Approved: 03/01/2016
Revised: 12/03/2019
Office of Environmental Health & Safety
940-898-3129
https://twu.edu/health-safety/
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page i
Table of Contents
I. PURPOSE .............................................................................................. 1
II. DEFINITIONS .......................................................................................... 2
III. COMPLIANCE ......................................................................................... 4
IV. APPLICABILITY ....................................................................................... 5
A. Relation to Lockout/Tagout (Hazardous Energy Control) Program .................................... 5 B. Work on Totally Enclosed Equipment ....................................................................... 5
1. Employer Responsibility ....................................................................................... 6 2. Employee Responsibility ...................................................................................... 6
C. Priority ........................................................................................................... 6 V. RISK ASSESSMENTS .................................................................................. 7
A. Risk Assessment Procedure ................................................................................... 7 B. Hierarchy of Risk Control Methods .......................................................................... 9 C. Arc Flash Risk Assessment .................................................................................... 9 D. Shock Risk Assessment ....................................................................................... 16
VI. JOB SAFETY PLANNING AND JOB BRIEFING ..................................................... 18
A. Job Safety Planning .......................................................................................... 18 B. Job Briefing.................................................................................................... 18 C. Change in Scope .............................................................................................. 18
VII. WORK INVOLVING ELECTRICAL HAZARDS ....................................................... 19
A. Equipment Operating at Less Than 50 Volts ............................................................. 21 B. Limited Approach Boundary ................................................................................ 21 C. Restricted Approach Boundary ............................................................................. 22 D. Arc Flash Protection Boundary ............................................................................. 22 E. Relationship Between Shock Hazard and Arc Flash Boundaries ......................................... 23 F. Physical Barriers ................................................................................................. 23
VIII. PERSONAL PROTECTIVE EQUIPMENT (PPE) ...................................................... 24
A. Arc Flash PPE .................................................................................................. 24 B. Shock Protection PPE ........................................................................................ 26 C. Other PPE ...................................................................................................... 27 D. PPE Care and Maintenance ................................................................................. 27
IX. INSULATED TOOLS AND EQUIPMENT ............................................................. 28
X. EQUIPMENT LABELING ............................................................................. 29
XI. ATTENDANTS ........................................................................................ 30
XII. ENERGIZED ELECTRICAL WORK PERMIT ......................................................... 31
XIII. GENERAL ENERGIZED ELECTRICAL WORK RULES ............................................... 33
XIV. EMPLOYEE TRAINING ............................................................................... 34
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page ii
XV. CONTRACTORS ...................................................................................... 35
XVI. ATTACHMENTS ...................................................................................... 37
A. Attachment 1 – Energized Electrical Work Permit ...................................................... 37
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 1
I. PURPOSE
This Electrical Work Safety Program has been developed in accordance with the following:
U.S. Occupational Safety and Health Administration (OSHA) regulations:
o 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout)
o 29 CFR 1910.333 – Selection and Use of Work Practices (Electrical Safety)
o 29 CFR 1910.137 – Electrical Protective Equipment Standard
National Fire Protection Association (NFPA) 70E, Standard for Electrical Safety in the
Workplace, Fifth Edition (2018)
This program establishes the minimum requirements for safe electrical work at Texas Woman’s
University (TWU) campuses and is applicable to the maintenance or service of equipment,
machines or electrical systems. This program is being implemented in order to reduce the
electrical hazards to employees conducting electrical work by requiring such work to be
conducted on electrically safe or de-energized equipment whenever possible, and requiring
proper procedures and equipment when energized work is necessary.
This program will apply to TWU employees and, where applicable as noted below, to contractors
who may be performing work on campus.
The intent of this program is to inform TWU employees and contractors of their roles and
responsibilities before, during, and following electrical work. These practices and procedures
are intended to provide for employee and contractor safety relative to electrical hazards in the
workplace.
Work place safety is in everyone’s best interest. Any violations of this program or any other
programs or standards should be reported immediately to your supervisor or EH&S.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 2
II. DEFINITIONS
The following regulatory definitions are relevant to the TWU Electrical Work Safety Program:
Arc Flash Hazard – A source of possible injury or damage to health associated with the release
of energy caused by an electric arc.
Arc Flash PPE Category – A number from 1 to 4 indicating the level of hazard/risk involved in
conducting energized work on a particular electrical system or equipment (where 4 is the
highest hazard/risk), and corresponding to levels of required personal protective equipment
(PPE).
Arc Flash Risk Assessment – A study investigating a worker’s potential exposure to arc flash
energy, conducted for the purpose of injury prevention and the determination of safe work
practices, arc flash protection boundary, and appropriate levels of personal protective
equipment (PPE).
Arc Flash Suit – A complete arc-rated clothing and equipment system that covers the entire
body, except for the hands and feet. This includes pants, jacket, and beekeeper-type hood
fitted with a face shield.
Arc Rating – The value attributed to materials that describes their performance to exposure to
an electrical arc discharge. The arc rating is expressed in cal/cm2 and is derived from the
determined value of the arc thermal performance value (ATPV) or energy of breakopen
threshold (EBT) (should a material system exhibit a breakopen response below the ATPV value)
derived from the determined value of ATPV or EBT, whichever is the lower value.
Balaclava (Sock Hood) – An arc-rated hood that protects the neck and head except for the
facial area of the eyes and nose. Balaclavas are worn with arc-rated face shields and helmets
when the head is within the arc flash protection boundary.
Boundary, Arc Flash – When an arc flash hazard exists, an approach limit from an arc source
at which incident energy equals 1.2 cal/cm2 (5 J/cm2). The arc flash boundary separates an
area in which a person is likely exposed to a second degree burn injury.
Boundary, Limited Approach – An approach limit at a distance from an exposed energized
electrical conductor or circuit part within which a shock hazard exists.
Boundary, Restricted Approach – An approach limit at a distance from an exposed energized
electrical conductor or circuit part within which there is an increased likelihood of electric
shock, due to electrical arc-over combined with inadvertent movement.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 3
Electrical Hazard – A dangerous condition such that contact or equipment failure can result in
electric shock, arc flash burn, thermal burn, or arc blast injury.
Electrically Safe Work Condition – A state in which an electrical conductor or circuit part has
been disconnected from energized parts, locked/tagged in accordance with TWU’s
Lockout/Tagout (Hazardous Energy Control) Program, tested to verify the absence of voltage,
and, if necessary, temporarily grounded for personnel protection.
Enclosed – Surrounded by a case, housing, fence, or wall(s) that prevents persons from
unintentionally contacting energized parts.
Energized – Electrically connected to, or is, a source of voltage.
Fault Current – The amount of current delivered as a point on the system during a short-circuit
condition. A fault current is a current that leaves the intended circuit path to return to the
source of supply.
Fault Current, Available – The largest amount of current capable of being delivered at a point
on the system during a short-circuit condition.
Hazard/Risk Class – See Arc Flash PPE Category.
Incident Energy – The amount of thermal energy impressed on a surface, a certain distance
from the source, generated during an electrical arc event. Incident energy is typically expressed
in calories per square centimeter (cal/cm2).
Lockout – The placement of a lockout device on an energy isolating device, in accordance with
an established program, ensures that the energy isolating device and the equipment being
controlled cannot be operated until the lockout device is removed.
Maintenance, Condition of – The state of the electrical equipment considering the
manufacturers’ instructions, manufacturers’ recommendations, and applicable industry codes,
standards, and recommended practices. The condition of maintenance for a piece of equipment
plays a major role in the safety of not only the maintenance employee but also the person
operating the equipment.
Normal Operating Condition – A normal operating condition exists when all of the following
conditions are satisfied:
The equipment is properly installed
The equipment is properly maintained
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 4
The equipment is used in accordance with instructions included in the listing and
labeling and in accordance with manufacturer’s instructions
The equipment doors are closed and secured
All equipment covers are in place and secured
There is no evidence of impending failure
Qualified Person – One who has demonstrated skills and knowledge related to the construction
and operation of electrical equipment and installations and has received safety training to
identify the hazards and reduce the associated risk. Such persons shall be familiar with the
proper precautionary techniques, applicable electrical policies and procedures, PPE, insulating
and shielding materials, and insulated tools and test equipment. A person can be considered
to be qualified with respect to certain equipment and methods but still be unqualified for
others.
Risk Assessment – An overall process that identifies hazards, eliminates the likelihood of
occurrence of injury or damage to health, estimates the potential severity of injury or damage
to health, and determines if protective measures are required.
Shock Hazard – A source of possible injury or damage to health associated with current through
the body caused by contact or approach to energized electrical conductors or circuit parts.
Injury and damage to health resulting from shock is dependent on the magnitude of the
electrical current, the power source frequency (e.g., 60 Hz, 50 Hz, dc), and the path and time
duration of current through the body. The physiological reaction ranges from perception,
muscular contractions, inability to let go, ventricular fibrillation, tissue burns, and death.
Working Distance – The distance between a person’s face and chest area and a prospective arc
source. Incident energy increases as the distance from the arc source decreases.
III. COMPLIANCE
All TWU employees and contractors are required to comply with the restrictions and limitations
imposed upon them by this program when conducting electrical work such as the installation,
removal, inspection, operation, maintenance, and demolition of electric conductors, electric
equipment, signaling and communications conductors and equipment, and raceways.
Only employees with proper skills and knowledge (i.e. Qualified Persons), including training on
both TWU’s Lockout/Tagout (Hazardous Energy Control) Program and this Electrical Work Safety
Program, may conduct electrical work in accordance with this program. Contractors must have
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 5
an electrical work safety program sufficient to protect TWU employees, students, and visitors
in place before beginning any applicable work on site.
IV. APPLICABILITY
A. Relation to Lockout/Tagout (Hazardous Energy Control) Program
Electrical work involving potential exposure to energized electrical conductors or circuit parts
should be avoided to the maximum extent possible. This includes any work where equipment
or electrical systems are not in an electrically safe work condition. In other words, electrical
work should be conducted under the TWU Lockout/Tagout Program except under the limited
exceptions provided in this program. If electrical work must be conducted on or near energized
electrical conductors or circuit parts, an Energized Electrical Work Permit justifying why the
work cannot be completed in an electrically safe work condition, and listing required safety
measures, must be issued before the work may proceed. The only exception to the requirement
to complete a permit is for work that is solely diagnostic, as described in Energized Electrical
Work Permit section below.
B. Work on Totally Enclosed Equipment Electrical work that does not involve any potential exposure to energized electrical
conductors or circuit parts is not normally covered by this program. However, if there is reason
to believe there is an increased likelihood of injury from exposure to an arc flash hazard from
equipment that is totally enclosed (such as malfunctioning equipment), the equipment should
be treated as if there are exposed energized parts, including use of an Energized Electrical
Work Permit.
Compliance with the TWU Lockout/Tagout Program is still required if employees or others are
exposed to other energy sources (e.g. steam, stored pressure, temperature extremes, moving
parts, etc.).
Examples of work on totally enclosed equipment include operating switches on equipment
which all covers, guards, and shielding are wholly intact. Nevertheless, the following practices
are recommended even when operating disconnects, control panels, switches, breakers, and
motor controls within enclosures with doors/panels closed and secured:
Wear non-melting clothes and safety glasses
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 6
Stand to the hinge side of door
Take a deep breath and face away from the switch before throwing it
4.3 Responsibility
Electrical safety is a shared responsibility between employers and employees. Employee
electrical safety requires a collaborative effort between workers and management.
1. Employer Responsibility
Texas Woman's University shall establish, document, and implement the safety-
related work practices and procedures required by the NFPA 70E standard and
provide employees with training in the same.
2. Employee Responsibility
The employee shall comply with the safety-related work practices and
procedures provided by Texas Woman's University. Regardless of the TWU
electrical safety plan, it is the employee who has the biggest impact on his or
her own electrical safety. Employees also have a responsibility to know their
limitations- only they can determine if they are truly qualified to safely perform
a task on a piece of equipment.
C. Priority
Hazard elimination shall be the first priority in the implementation of safety-related work
practices. The electrical safety program shall include a risk assessment procedure and shall
comply with NFPA 70E 110.1(H)(1) through 110.1(H)(3).
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 7
V. RISK ASSESSMENTS
A. Risk Assessment Procedure The following risk assessment procedures shall address employee exposure to electrical
hazards and shall identify the process to be used before work is started to carry out the
following:
Identify hazards
Assess risks
Implement risk control according to the hierarchy of risk control methods
The flowchart on the next page describes the process of a risk assessment.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 8
Conduct risk assessments
Shock risk
assessments
Determine shock protection
boundaries
Limited approach
boundary
Restricted approach
boundary
Determine required shock PPE
Determine appropriate safety-related work practices
Arc flash risk
assessments
Determine likelihood of arc
flash occurring
Select an arc flash risk assessment
method
PPE category
method
Limited approach
boundary
DC
equipment
AC
equipment
Confirm
compliance
Confirm
compliance
Obtain arc flash boundary and
PPE category
Obtain arc flash boundary and
PPE category
Determine required arc-rated PPE
Calculate arc flash boundary
and incident energy at working
distance
Determine required arc-rated
PPE
Document risk assessment
Label equipment
Re-evaluate risk assessments
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 9
B. Hierarchy of Risk Control Methods
The risk assessment procedure shall require that preventive and protective risk controls be
implemented in accordance with the following hierarchy:
Elimination
Substitution
Engineering controls
Awareness
Administrative controls
PPE
C. Arc Flash Risk Assessment
TWU shall conduct an arc flash risk assessment of the electrical systems employees will be
working with to identify arc flash hazards, estimate the likelihood of occurrence of injury or
damage to health and the potential severity of injury or damage to health, and to determine if
additional protective measures are required, including the use of PPE. The arc flash risk
assessments should evaluate each piece of equipment or at each point in the electrical system
where TWU employees will conduct work. Where this is not feasible, the analysis will be
conducted as far “downstream” (load side) in the electrical system as possible. Due to the
technical complexity of an arc flash risk assessment, it will generally be conducted by an
outside electrical engineering firm who will follow the assessment procedures in NFPA70E. The
assessment must take into consideration the design of the overcurrent protective devices and
opening time, including its condition of maintenance.
Once an arc flash risk assessment has been conducted, it must be updated when a major
modification or renovation takes place. Arc flash risk assessments must also be reviewed
periodically, at intervals not exceeding 5 years.
The results of the arc flash risk assessment will include, at a minimum: the identification of
the equipment analyzed, appropriate safety-related work practices, the arc flash boundary in
feet, the PPE to be used within the arc flash boundary, and all backup data indicating how
these results were obtained (such as the design of the electrical equipment, operating condition
and condition of maintenance). If an arc flash hazard does not exist for a piece of equipment
or point in system, that information will be documented as well.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 10
For equipment or points in the system that have not yet been specifically evaluated as part of
the arc flash risk assessment, one of two approaches may be taken to determine the arc flash
hazard:
1. Assume that electrical systems and attached equipment will have the same potential
arc flash hazards as the nearest analyzed “upstream” (line side) point in the system, or
2. For tasks involving exposure to voltages less than 600 volts (involving equipment that
has not been specifically evaluated as part of the arc flash risk assessment), use Tables
1, 2, and 3 below to identify the required arc flash PPE for the task and voltage in
question.
Tables 1, 2, and 3 may not be used for equipment/systems that have been specifically
evaluated as part of the arc flash risk assessment.
Important: Pay particular attention to the notes at the bottom of the table; if the equipment
in question is known to not meet the specifications listed in the notes (whether due to original
equipment specifications or maintenance issues) Table 1 cannot be used.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 11
Table 1 – Arc Flash Hazard Identification for Alternating-Current (AC) and Direct-Current (DC) Systems
Task Equipment Condition* Arc Flash PPE Required
Reading a panel meter while operating a meter switch
Any No
Normal operation of a circuit breaker (CB), switch, contactor, or starter
Normal operating condition No
Other than normal operating condition Yes
For ac systems: Work on energized electrical conductors and circuit parts, including voltage testing
Any Yes
For dc systems: Work on energized electrical conductors and circuit parts of series-connected battery cells, including voltage testing
Any Yes
Voltage testing on individual battery cells or individual multi-cell units
Normal operating condition No
Other than normal operating condition Yes
Removal or installation of CBs or switches Any Yes
Removal or installation of covers for equipment such as wireways, junction boxes, and cable trays that does not expose bare energized electrical conductors and circuit parts
Normal operating condition No
Other than normal operating condition Yes
Removal of bolted covers (to expose bare energized electrical conductors and circuit parts). For dc systems, this includes bolted covers such as battery terminal covers.
Any Yes
Removal of battery intercell connector covers Normal operating condition No
Other than normal operating condition Yes
Opening hinged door(s) or cover(s) to expose bare energized electrical conductors and circuit parts
Any Yes
Perform infrared thermography and other noncontact inspections outside the restricted approach boundary. This activity does not include opening of doors or covers.
Any Yes
Application of temporary protective grounding equipment after voltage test
Any Yes
Work on control circuits with exposed energized electrical conductors and circuit parts, 120 volts or below without any other exposed energized equipment over 120 V including opening of hinged covers to gain access
Any No
Work on control circuits with exposed energized electrical conductors and circuit parts, greater than 120 V
Any Yes
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 12
Task Equipment Condition* Arc Flash PPE Required
Insertion or removal of individual starter buckets from motor control center (MCC)
Any Yes
Insertion or removal (racking) of CBs or starters from cubicles, doors open or closed
Any Yes
Insertion or removal of plug-in devices into or from busways
Any Yes
Insulated cable examination with no manipulation of cable
Any No
Insulated cable examination with manipulation of cable
Any Yes
Work on exposed energized electrical conductors and circuit parts of equipment directly supplied by a panelboard or motor control center
Any Yes
Insertion and removal of revenue meters (kW-hour, at primary voltage and current)
Any Yes
For dc systems, insertion or removal of individual cells or multi-cell units of a battery system in an enclosure
Any Yes
For dc systems, insertion or removal of individual cells or multi-cell units of a battery system in an open rack
Any No
For dc systems, maintenance on a single cell of a battery system or multi-cell units in an open rack
Any No
For dc systems, work on exposed energized electrical conductors and circuit parts of utilization equipment directly supplied by a dc source
Any Yes
Arc-resistant switchgear Type 1 or 2 (for clearing times of <0.5 sec with a prospective fault current not to exceed the arc-resistant rating of the equipment) and metal enclosed interrupter switchgear, fused or unfused of arc resistant type construction, tested in accordance with IEEE C37.20.7:
Insertion or removal (racking) of CBs from cubicles
Insertion or removal (racking) of ground and test device
Insertion or removal (racking) of voltage transformers on or off the bus
Normal operating condition No
Other than normal operating condition Yes
Opening voltage transformer or control power transformer compartments
Any Yes
Outdoor disconnect switch operation (hookstick operated) at 1kV through 15kV
Any Yes
Outdoor disconnect switch operation (gang-operated, from grade) at 1kV through 15kV
Any Yes
Note: Hazard identification is one component of risk assessment. Risk assessment involves a determination of the likelihood of occurrence of an incident, resulting from a hazard that could cause injury or damage to health. The assessment of the likelihood of occurrence contained in this table does not cover every possible condition or situation. Where this table indicates that arc flash PPE is not required, an arc flash is not likely to occur. * The phrase properly installed, as used in this table, means that the equipment is installed in accordance with applicable industry codes and standards and the manufacturer’s
recommendations. The phrase properly maintained, as used in this table, means that the equipment has been maintained in accordance with the manufacturer’s recommendations and applicable industry codes and standards. The phrase evidence of impending failure, as used in this table, means that there is evidence of arcing, overheating, loose or bound equipment parts, visible damage, deterioration, or other damage.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 13
Table 2 – Arc Flash Hazard PPE Categories for Alternating-Current (AC) Systems
Equipment Arc Flash PPE Category Arc-Flash Boundary
Panelboards or other equipment rated 240 V and below Parameters: Maximum of 25 kA available fault current; maximum of 0.03 sec (2 cycles) fault clearing time; minimum working distance 455 mm (18 in.)
1 19 in.
Panelboards or other equipment rated >240 V and up to 600 V Parameters: Maximum of 25 kA available fault current; maximum of 0.03 sec (2 cycles) fault clearing time; minimum working distance 455 mm (18 in.)
2 3 ft.
600-V class motor control centers (MCCs) Parameters: Maximum of 65 kA available fault current; maximum of 0.03 sec (2 cycles) fault clearing time; minimum working distance 455 mm (18 in.)
2 5 ft.
600-V class motor control centers (MCCs) Parameters: Maximum of 42 kA available fault current; maximum of 0.33 sec (20 cycles) fault clearing time; minimum working distance 455 mm (18 in.)
4 14 ft.
600-V class switchgear (with power circuit breakers or fused switches) and 600 V class switchboards Parameters: Maximum of 35 kA available fault current; maximum of up to 0.5 sec (30 cycles) fault clearing time; minimum working distance 455 mm (18 in.)
4 20 ft.
Other 600-V class (277 V through 600 V, nominal) equipment Parameters: Maximum of 65 kA available fault current; maximum of up to 0.03 sec (2 cycles) fault clearing time; minimum working distance 455 mm (18 in.)
2 5 ft.
NEMA E2 (fused contactor) motor starters, 2.3 kV through 7.2 kV Parameters: Maximum of 35kA available fault current; maximum of up to 0.24 sec (15 cycles) fault clearing time; minimum working distance 910 mm (36 in.)
4 40 ft.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 14
Equipment Arc Flash PPE Category Arc-Flash Boundary
Metal-clad switchgear, 1 kV through 15 kV Parameters: Maximum of 35 kA available fault current; maximum of up to 0.24 sec (15 cycles) fault clearing time; minimum working distance 910 mm (36 in.)
4 40 ft.
Arc-resistant switchgear 1 kV through 15 kV [for clearing times of < 0.5 sec (30 cycles) with an available fault current not to exceed the arc-resistant rating of the equipment], and metal-enclosed interrupter switchgear, fused or unfused of arc-resistant-type construction, 1 kV through 15 kV Parameters: Maximum of 35 kA short-circuit current available; maximum of up to 0.24 sec (15 cycles) fault clearing time; working distance 910 mm (36 in.)
Doors Closed: N/A N/A
Doors Open: 4 40 ft.
Other equipment 1 kV through 15 kV Parameters: Maximum of 35 kA available fault current; maximum of up to 0.24 sec (15 cycles) fault clearing time; minimum working distance 910 mm (36 in.)
4 40 ft.
Note: For equipment rated 600 volts and below, and protected by upstream current-limiting fuses or current-limiting circuit breakers sized at 200 amperes or less, the arc flash PPE category can be reduced by one number but not below arc flash PPE Category 1.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 15
Table 3 – Arc Flash Hazard PPE Categories for Direct-Current (DC) Systems
Equipment Arc Flash PPE Category
Arc-Flash Boundary
Storage batteries, dc switchboards, and other dc supply sources Parameters: 100 V ≥ voltage ≥ 250 V Maximum arc duration and working distance: 2 sec @ 455 mm (18 in.)
Available fault current < 4 kA 2 3 ft.
4 kA ≤ available fault current < 7 kA 2 4 ft.
7 kA ≤ short-circuit current < 15 kA 3 6 ft.
Storage batteries, dc switchboards, and other dc supply sources Parameters: 250 V < Voltage ≤ 600 V Maximum arc duration and working distance: 2 sec @ 455 mm (18 in.)
Available fault current < 1.5 kA 2 3 ft.
1.5 kA ≤ available fault current < 3 kA 2 4 ft.
3 kA ≤ available fault current < 7 kA 3 6 ft.
7 kA ≤ available fault current < 10 kA 4 8 ft.
Notes:
1. Apparel that can be expected to be exposed to electrolyte must be evaluated for electrolyte protection per ASTM F1296 as well as be arc rated. Contact the Office of Environmental Health & Safety for assistance.
2. A two-second arc duration is assumed if there is no overcurrent protective device (OCPD) or if the fault clearing time is not known. If the fault clearing time is known and is less than 2 seconds, an incident energy analysis could provide a more representative result.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 16
D. Shock Risk Assessment TWU is also required to perform an analysis of the shock hazards for each piece of equipment
or at each point in the electrical system where TWU employees will conduct work. This may
be determined as part of the arc flash risk assessment, but must also be evaluated immediately
prior to conducting the work as part of preparing an Energized Electrical Work Permit.
Employees and their supervisors must evaluate the shock hazards associated with all exposed
electrical conductors and circuit parts in the area of the work task in question to estimate the
likelihood of occurrence of injury or damage to health and the potential severity of injury or
damage to health, as well as to determine if additional protective measures are required,
including the use of PPE.
If additional protective measures are required, they shall be selected and implemented
according to the hierarchy of risk control. When the additional protective measures include the
use of PPE, the following shall be determined:
The voltage to which personnel will be exposed
The boundary requirements
The personal and other protective equipment required to protect against the shock
hazard
The results of a shock risk assessment shall be documented and will include the limited
approach and restricted approach boundaries in feet. The aforementioned boundaries shall be
applicable where personnel are approaching exposed energized electrical conductors or circuit
parts.
The limited approach and restricted approach boundaries are determined by reviewing all
energized electrical conductors or circuit parts that employees are exposed to during a
particular task (generally all electrical conductors or circuit parts that are not fully enclosed).
The nominal system voltage range (phase to phase) determines the boundary distances from
any part of the exposed electrical conductors or circuit parts.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 17
Table 4 – Shock Hazard Approach Boundaries for Alternating-Current (AC) Systems
Nominal System Voltage, Phase to Phase*
Limited Approach Boundary Restricted Approach Boundary; Includes Inadvertent Movement Adder
Exposed Movable Conductor **
Exposed Fixed Circuit Part
Less than 50V Not specified Not specified Not specified
50 to 150V 10 ft 0 in 3 ft 6 in Avoid contact
151 to 750V 10 ft 0 in 3 ft 6 in 1 ft 0 in
751 to 15kV 10 ft 0 in 5 ft 0 in 2 ft 2 in * For single phase systems above 250V, select the range that is equal to the maximum phase-to-ground voltage multiplied by 1.732. ** Exposed movable conductors describes a condition in which the distance between the conductor and a person is not under the control of the person. The term is normally
applied to overhead line conductors supported by poles.
Table 5 – Shock Hazard Approach Boundaries for Direct-Current (DC) Systems
Nominal Potential Difference
Limited Approach Boundary Restricted Approach Boundary; Includes Inadvertent Movement Adder
Exposed Movable Conductor *
Exposed Fixed Circuit Part
Less than 50V Not specified Not specified Not specified
50 to 300V 10 ft 0 in 3 ft 6 in Avoid contact
301 to 1kV 10 ft 0 in 3 ft 6 in 1 ft 0 in
1.1 to 5kV 10 ft 0 in 5 ft 0 in 1 ft 5 in * Exposed movable condition describes a condition in which the distance between the conductor and a person is not under the control of the person. The term is normally
applied to overhead line conductors supported by poles.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 18
VI. JOB SAFETY PLANNING AND JOB BRIEFING
Before starting each job that involves exposure to electrical hazards, the employee in charge
shall complete a job safety plan and conduct a job briefing with the employees involved.
A. Job Safety Planning
The job safety plan shall be in accordance with the following:
Be completed by a qualified person
Be documented
Include the following information:
o A description of the job and the individual tasks
o Identification of the electrical hazards associated with each task
o A shock risk assessment for tasks involving a shock hazard
o An arc flash risk assessment for tasks involving an arc flash hazard
o Work procedures involved, special procedures, and energy source controls
B. Job Briefing
The job briefing shall cover the job safety plan and the information on the energized electrical
work permit, if a permit is required. Where exposure to potential electrical hazards is
involved, the employee in charge should be qualified for the tasks to be performed (i.e., for
working at the applicable voltage).
C. Change in Scope
Additional job safety planning and job briefings shall be held if changes occur during the course
of the work that might affect the safety of employees. Any change in scope, procedure, task,
safety, and so forth must not be done without consideration for the effect of that change on
the risk assessment, work permit, and worker safety.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 19
VII. WORK INVOLVING ELECTRICAL HAZARDS
This section outlines the requirements for work involving electrical hazards such as the
electrical safety-related work practices, assessments, precautions, and procedures when an
electrically safe work condition cannot be established. The arc flash protection boundary
determined by the arc flash risk assessment, and the limited approach and restricted approach
boundaries determined by the shock risk assessment, must be enforced and adhered to at all
times by TWU employees and contractors.
A sample flowchart outlining the thought process behind conducting electrical work can be
found on the next page.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 20
Is equipment within conditions permitting
normal operation?
Does interaction include other than normal equipment
operation?
Is it an electrically safe work condition required?
Is there justification for
energized electrical work?
Is an energized
work permit
required?
Is arc flash
boundary crossed?
Normal operation permitted
Interaction/operation
not permitted
Conduct risk assessments
No PPE
required
PPE
required
Conduct a job briefing
Conduct a job briefing
Establish an electrically safe work condition
Complete energized
work permit
Conduct justified
energized work
Consider work permit for
exempt conditions
Consider work permit for
exempt conditions
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 21
A. Equipment Operating at Less Than 50 Volts Under normal conditions, electrical conductors energized at a voltage level less than 50 volts
do not present an electrical shock hazard. As a result, Table 4 and Table 5 list “Not Specified”
for the various boundaries. Energized electrical conductors and circuit parts that operate at
less than 50 volts shall not be required to be de-energized where the capacity of the source
and any overcurrent protection between the energy source and the worker are considered and
it is determined that there will be no increased exposure to electrical burns or to explosion due
to electric arcs.
However, a thermal hazard can exist in circuits that have a significant capacity to deliver
energy, even when the voltage level is less than 50 (for example, battery installations where
arcing could result from a short circuit). Only Qualified Persons who have an adequate level of
experience for the particular task being conducted should perform work on equipment with less
than 50 volts; and they should undertake appropriate safety precautions even if not specified
above.
B. Limited Approach Boundary The limited approach boundary may only be crossed by Qualified Persons (as defined above)
who have an adequate level of experience for the particular task being conducted, and who
have completed the training required by the Employee Training section below.
The determination of who is a Qualified Person for a particular task must be determined jointly
by supervisors overseeing the work, and the employee(s) conducting the work.
All unqualified persons (other employees, contractors, students, etc.) must be prevented from
crossing the limited approach boundary. If an unqualified person must cross the limited
approach boundary, that person must be directly and continuously supervised by a Qualified
Person.
Any tools and/or handling equipment within the limited approach boundary must be
appropriately insulated as per the Insulated Tools and Equipment section below. Conductive
articles of clothing or jewelry that could present an electrical hazard shall also not be worn
within the limited approach boundary.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 22
Anyone within the limited approach boundary must be alert at all times; no one will be
permitted to cross the limited approach boundary while their alertness is impaired due to
illness, fatigue, or other reasons.
C. Restricted Approach Boundary The restricted approach boundary may only be crossed by Qualified Persons who have an
adequate level of experience for the particular task being conducted AND are protected by PPE
suitable for the full circuit voltage AND must possess a signed Energized Electrical Work Permit.
The appropriate voltage rated PPE must cover any part of the body within the restricted
approach boundary. For restricted approach boundaries listed as “Avoid Contact” in Table 4
and Table 5 above, the appropriate voltage rated PPE must cover any part of the body that may
come in contact with energized electrical conductors or circuit parts. If the voltage rated PPE
cannot protect all parts of the body that may come in contact with energized parts, voltage
rated insulating blankets, covers or similar equipment must be used.
No unqualified persons may cross the restricted approach boundary for any reason, even if
they are supervised by a Qualified Person.
“Crossing” the restricted approach boundary is defined as both crossing it with any body part,
or crossing it with any tool or piece of equipment (i.e. a Qualified Person may not avoid the
need for an Energized Electrical Work Permit by keeping their body outside of the boundary but
crossing it with a tool).
D. Arc Flash Protection Boundary The arc flash protection boundary may only be crossed by individuals protected from thermal
hazards by appropriate arc-rated PPE. Appropriate arc-rated PPE is that which has a sufficient
arc rating for the equipment the work is being conducted on as determined by an arc flash risk
assessment, and indicated on equipment labels (see below).
As discussed in the Arc Flash Risk Assessment section above, if the arc flash risk assessment has
not been conducted for the particular equipment to be worked on, the arc flash hazards
(including the arc flash protection boundary) will be presumed to be the same as the nearest
analyzed “upstream” point in the system. Alternately, for tasks involving exposure to voltages
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 23
less than 600 volts, Table 2 or 3 may be used to determine the appropriate arc-rated PPE to
be used.
The appropriate arc-rated PPE will cover any part of the body that crosses the arc flash
protection boundary.
Important: If the arc flash analysis indicates that the thermal hazards exceed 40 cal/cm2
(greater than the hazard requiring PPE Category 4), then work on the affected equipment will
only be permitted in accordance with the TWU Lockout/Tagout Program (i.e. work on or near
such energized electrical conductors or circuit parts is not permitted).
E. Relationship Between Shock Hazard and Arc Flash Boundaries Shock hazard boundaries will always have the same relation to each other, the restricted
approach boundary will be closest to the electrical equipment and the limited approach
boundary will be the farthest (See Table 4 and Table 5). However, the arc flash protection
boundary distance can vary significantly depending on the specifics of the electrical equipment,
and may not always fall at the same point in relation to the shock protection boundaries. In
other words, the arc flash protection boundary may be farther from the energized parts than
the limited approach boundary, could be very close to the restricted approach boundary, or
somewhere in between. Therefore, the requirements for crossing the arc flash protection
boundary must be adhered to as well as the appropriate shock protection boundary. For
example; unqualified personnel crossing the arc flash protection boundary and the limited
approach boundary would have to be wearing appropriate arc flash PPE AND be escorted by a
Qualified Person at all times.
F. Physical Barriers Physical barriers consisting of caution tapes, sawhorses, portable gates or similar must be
placed at the limited approach boundary or the arc flash protection barrier, whichever is
farther from the energized conductor or circuit part, to prevent unqualified individuals from
entering the area. If the electrical work is being conducted in a small area with adequate
access control (e.g. a small locked mechanical room), physical barriers may not be required.
However, if the area is sufficiently large that other employees or contractor could enter the
area without the knowledge of the Qualified Person(s) conducting the work, then barriers will
still be required.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 24
If physical barriers may not be sufficient to prevent unqualified individuals from entering the
area, an attendant will be stationed to warn and prevent unqualified individuals from
entering the area.
VIII. PERSONAL PROTECTIVE EQUIPMENT (PPE)
PPE for electrical work must be selected and used to protect against both shock hazards and
arc flash hazards in accordance with the Risk Assessment and Job Safety Analysis sections
above. In short, shock protection PPE must be rated for the full voltage of any exposed
energized conductor or circuit part the employee could be exposed to, and arc flash PPE must
meet the rating determined by the arc flash analysis as described below.
Employees exposed to electrical hazards when the risk associated with that hazard is not
adequately reduced by the applicable electrical installation requirements shall be provided
with, and shall use, protective equipment that is designed and constructed for the specific part
of the body to be protected and for the work to be performed.
PPE for electrical work must be selected and used to protect against both shock hazards and
arc flash hazards in accordance with the Risk Assessment and Job Safety Analysis sections
above. In short, shock protection PPE must be rated for the full voltage of any exposed
energized conductor or circuit part the employee could be exposed to, and arc flash PPE must
meet the rating determined by the arc flash analysis as described below.
A. Arc Flash PPE Arc flash personal protective equipment (PPE) protects primarily against thermal hazards and
is rated by the incident energy (in cal/cm2) it is capable of withstanding, known as an arc rating.
A “PPE Category” consists of pieces of PPE which are worn together and which all have a certain
minimum arc rating. Table 6 below indicates the requirements at TWU for each PPE Category.
The appropriate PPE Category is primarily determined by the results of the Arc Flash Risk
Assessment which will list the potential incident energy from which the proper PPE Category
can be found, or will provide the PPE Category specifically (on older labels). Alternatively,
where the risk assessment and equipment labeling has not been done, PPE Category can be
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 25
determined by selecting the appropriate task and voltage from Table 1 or Tables 2 and 3 if the
maximum voltage is less than 600 volts.
Table 6 – Arc Flash PPE Requirements
PPE Category
Required PPE Description
1
Arc-Rated Clothing – required minimum arc rating 4 cal/cm2 o Arc-rated long-sleeve shirt and pants or arc-rated coverall o Arc-rated face shield or arc flash suit hood o Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Protective Equipment o Hard hat o Safety glasses or goggles (SR) o Hearing protection (ear canal inserts) o Heavy duty leather gloves o Leather footwear
2
Arc-Rated Clothing – required minimum arc rating 8 cal/cm2 o Arc-rated long-sleeve shirt and pants or arc-rated coverall o Arc-rated flash suit hood or arc-rated face shield and arc-rated balaclava o Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Protective Equipment o Hard hat o Safety glasses or goggles (SR) o Hearing protection (ear canal inserts) o Heavy-duty leather gloves o Leather footwear
3
Arc-Rated Clothing – required minimum arc rating 25 cal/cm2 o Arc-rated long-sleeve shirt (AR) o Arc-rated pants (AR) o Arc-rated coverall (AR) o Arc-rated flash suit jacket and pants (AR) o Arc-rated flash suit hood o Arc-rated gloves o Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Protective Equipment o Hard hat o Safety glasses or goggles (SR) o Hearing protection (ear canal inserts) o Leather footwear
4
Arc-Rated Clothing – required minimum arc rating 40 cal/cm2 o Arc-rated long-sleeve shirt (AR) o Arc-rated pants (AR) o Arc-rated coverall (AR) o Arc-rated flash suit jacket and pants (AR) o Arc-rated flash suit hood o Arc-rated gloves o Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Protective Equipment o Hard hat o Safety glasses or goggles (SR) o Hearing protection (ear canal inserts) o Leather footwear
AN: As needed (optional). AR: As required. SR: Selection required.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 26
As noted above, if the arc flash analysis indicates that the thermal hazards exceed 40 cal/cm2
(required for PPE Category 4), then work on the affected equipment will only be permitted in
accordance with the TWU Lockout/Tagout Program (i.e. work on or near such energized
electrical conductors or circuit parts is not permitted).
Voltage rated gloves and leather protectors provide adequate arc flash/thermal protection for
the hands, and do not have to have a specific arc-rating. Leather footwear is required for all
PPE Categories, but do not have to meet a minimum arc rating.
Note that only those parts of the body that are within the arc flash protection boundary must
be protected with PPE necessary to protect from the thermal hazards. Table 6 assumes that
the entire body will be within this boundary, but there may be some instances where this is not
the case.
Either arc-rated, flame resistant or non-melting flammable materials may be worn under arc
flash PPE meeting the requirements of Table 6, but meltable fibers such as acetate, nylon,
polyester, polypropylene, and spandex, may not be. Employees who conduct electrical work
must not wear clothing with meltable fibers other than incidental amount of elastic in
underwear and socks.
Outerwear such as rain gear and parkas must also be arc-rated. Use of any such clothing or
other items such as hard hat liners that are not arc-rated is prohibited within the arc flash
protection boundary.
Arc flash clothing must cover potentially exposed areas as completely as possible. Sleeves shall
be fastened at the wrists, shirts will be tucked into pants, and shirts, coveralls, and jackets
shall be closed at the neck. Tight-fitting clothing shall be avoided as loose fitting clothing
provides more thermal protection. However, the apparel must interfere with the work task as
little as possible while still providing the required protection.
B. Shock Protection PPE As noted in the Restricted Approach Boundary section above, the appropriate voltage rated PPE
must cover any part of the body within the restricted approach boundary. For restricted
approach boundaries listed as “Avoid Contact” in Table 4 and Table 5 above, the appropriate
voltage rated PPE must cover any part of the body that may come in contact with energized
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 27
electrical conductors or circuit parts. If the voltage rated PPE cannot protect all parts of the
body that may come in contact with energized parts, voltage rated insulating blankets, covers
or similar equipment must be used.
Shock protection PPE for the hands generally consists of insulating gloves with leather
protectors. Insulating gloves must be rated for the maximum voltage of any exposed energized
electrical conductors or circuit parts. Leather protectors must always be worn over insulating
gloves to prevent compromising the insulating properties of the inner gloves, and to provide
additional thermal protection.
If there is a potential for contact of the head with energized electrical conductors or circuit
parts, nonconductive head protection must be worn. This can generally be accomplished by
wearing an arc-rated helmet and face shield. If the risk of contact is only to the top of the
head, a Class E hard hat is sufficient. Appropriate hard hats are incorporated into arc-rated
face shields and suit hoods used at TWU.
If work on energized electrical conductors or circuit parts involves step and touch sock potential
(from stepping on live conductors, or standing on conductive surfaces for example), then
dielectric overshoes must also be used.
C. Other PPE
Safety glasses must be worn whenever conducting work on energized electrical conductors or
circuit parts, even when the head is not in the arc flash protection boundary. Eye injuries can
occur from arc blasts, even when outside of the arc flash protection boundary, and from normal
work that might cause flying objects. Safety glasses must be also be worn beneath face shields
or arc flash suit hoods to adequately protect the eyes from flying objects during an arc flash
incident.
Hearing protection (consisting of ear canal insert type ear plugs) must also be worn whenever
conducting work within the arc flash protection boundary to protect against the noise
associated with a potential arc blast.
D. PPE Care and Maintenance
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 28
All PPE must be inspected by the user prior to each use, and immediately following any incident
that can reasonably be suspected of having caused damage. Any PPE that is damaged or
contaminated (with grease, oil or flammable liquids) shall not be used. PPE shall be maintained
in a safe, clean, and reliable condition and in accordance with the manufacturer’s instructions.
PPE shall be stored in a manner that prevents damage from physically damaging conditions and
from moisture, dust, other deteriorating agents or contamination.
In addition to the above visual inspection, insulating gloves and sleeves must be “air tested”
daily before use. This is completed by rolling the cuff tightly to trap air inside; applying
pressure to areas of the glove, and listening for escaping air. The glove is then turned inside
out and the air test is repeated.
Electrical shock protective equipment shall be tested by an outside testing firm in accordance
with ASTM standards. Blankets and sleeves must be tested every 12 months, and gloves must
be tested every 6 months. If gloves have been tested but are not yet in use, they may be
retested every 12 months.
IX. INSULATED TOOLS AND EQUIPMENT
Employees shall use insulated tools (including test equipment) and/or handling equipment when
working inside the limited approach boundary as per the following:
Insulated tools shall be rated for the maximum voltage of any exposed conductor or
circuit part that the tool could come in contact with.
Insulated tools shall be designed and constructed for the environment to which they are
exposed and the manner in which they are used.
Insulated tools shall be protected from damage to the insulating material.
Fuse or fuseholder handling equipment, insulated for the circuit voltage, must be used
to remove or install fuses that are energized.
Ropes and handlines used within the limited approach boundary must be nonconductive.
Portable ladders must have nonconductive side rails when used inside the limited
approach boundary or where the employee or ladder could contact exposed energized
electrical conductors or circuit parts.
Protective shields, protective barriers, or insulating materials shall be used to protect
each employee from shock, burns, or other electrically related injuries while an
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 29
employee is working within the limited approach boundary of energized conductors or
circuit parts that might be unintentionally contacted or where dangerous electric
heating or arcing might occur. Insulated covers, shields, or similar equipment must be
used if voltage rated PPE cannot protect all parts of the body that may unintentionally
come in contact with energized electrical conductors or circuit parts.
Insulated tools and equipment shall be inspected prior to each use. The inspection will look
for damage to the insulation or damage that may limit the tool from performing its intended
function or increase the potential for an incident (e.g. damaged tip on a screwdriver). If any
issues are noted during the visual inspection, the equipment will immediately be taken out of
service. Rubber covers, shields and line hose needs to be tested by an outside testing firm in
accordance with ASTM standards if the insulating value is suspect due to physical damage,
wear or other issues noted during inspection.
In addition to the above requirements, electrical test equipment used for the testing for the
absence of voltage on conductors or circuit parts must be verified to be operating properly
before and after the voltage test is performed. This is generally achieved by using the test
equipment on electrical equipment such as a nearby outlet that is known to be energized.
X. EQUIPMENT LABELING
Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket
enclosures, and motor control centers that are in other dwelling units and that are likely to
require examination, adjustment, servicing, or maintenance while energized shall be marked
with a label containing the results of the arc flash and shock risk assessments for that piece of
equipment.
The labels shall read “WARNING: ARC FLASH AND SHOCK HAZARD” or similar, and will have
graphics and/or colors to make them stand out from the equipment and surrounding labels.
The labels shall contain the following information:
The identity of the equipment
The date of the arc flash risk assessment
Arc flash protection boundary in feet
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 30
Available incident energy in cal/cm2 (and the corresponding working distance) or the
arc flash PPE Category required by the equipment (but not both)
The nominal system voltage
The limited approach boundary in feet/inches
The restricted approach boundary in feet/inches
If the arc flash analysis indicates that the thermal hazards of working on a piece of equipment
exceed 40 cal/cm2, this will be indicated on the label and the arc flash and shock hazard
boundaries will not need to be listed as live work is prohibited on such equipment.
XI. ATTENDANTS
Any work on energized electrical conductors or circuit parts must involve at least two Qualified
Persons, one of which will act as the Attendant who will be equipped with communication
equipment and will summon emergency assistance as necessary. TWU Department of Public
Safety (DPS) is trained and equipped (including automatic external defibrillators) to provide
first aid to TWU employees. The Attendant shall be stationed to keep unqualified employees
outside a work area where the unqualified employee might be exposed from electrical hazards.
The Attendant shall remain in the area as long as there is a potential for employees to be
exposed to the electrical hazards. The Attendant should have no other duty than to deliver the
warning.
Exception: An attendant is not required if the work is solely diagnostic in nature AND the task
involves exposure to voltages less than 600 volts. Work that is considered solely diagnostic
would include visual inspection and crossing the restricted approach boundary to use voltage
meters and similar diagnostic equipment. Any work that involves tightening electrical
connections, adding or removing conductors or circuit parts or other modification to the
equipment is NOT diagnostic and requires an attendant. However, having an attendant is still
STRONGLY encouraged as shock and arc flash hazards still exist when conducting diagnostic
work, and without an attendant there may be no one to assist in an emergency.
The Attendant must not cross the restricted approach boundary as part of the work task. Thus
if a task requires more than one employee to cross the restricted approach boundary, there
must always be one additional employee to act as the attendant (e.g. if the task requires two
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 31
employees within the restricted approach boundary, then a third employee is required to act
as the Attendant).
The Attendant must be equipped with the PPE required based on the shock and arc flash hazard
boundaries he or she will be crossing.
If an electrical injury occurs, the Attendant must FIRST remove the source of electricity if he
can do so safely, THEN request emergency assistance from DPS.
XII. ENERGIZED ELECTRICAL WORK PERMIT
No work may be performed within the restricted approach boundary unless the work meets one
of the following exceptions:
1. De-energizing the equipment poses additional or increased hazards (acceptable
examples include interruption of life support equipment, deactivation of emergency
alarm systems, and shutdown of hazardous location ventilation equipment),
2. The task to be performed is infeasible in a de-energized state due to equipment design
or operational limitations (acceptable examples include performing diagnostics and
testing of electrical circuits that can only be performed with the circuit energized and
work on circuits that form and integral part of a continuous process that would otherwise
need to be completely shut down in order to permit work on one circuit or piece of
equipment), or
3. The energized electrical conductors and circuit parts operate at less than 50 volts to
ground and there is no increased exposure to electrical burns or to explosion due to
electric arcs.
IF THE TASK DOES NOT meet one of the above exceptions; it MUST BE conducted under the
requirements of the TWU Lockout/Tagout program (i.e. live work is not permitted).
IF THE TASK DOES meet one of the above exceptions; it MUST BE performed under an
authorized Energized Electrical Work Permit. A copy of the permit can be found in Attachment
1 below.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 32
In addition to work performed within the restricted approach boundary, an Energized Electrical
Work Permit is required if an employee is to interact with equipment when conductors or circuit
parts are not exposed but an increased likelihood of injury from an exposure to an arc flash
hazard exists.
Exception: An Energized Electrical Work Permit is not required if the work is solely diagnostic
in nature. Work that is considered solely diagnostic would include thermal, ultrasound, and
visual inspections and crossing the restricted approach boundary to use voltage meters and
similar diagnostic equipment. Any work that involves tightening electrical connections, adding
or removing conductors or circuit parts or other modification to the equipment is NOT
diagnostic and requires a permit. Even if diagnostic work is being conducted without a permit,
all of the other rules under this program must be followed, including use of proper PPE for
the applicable shock and arc flash hazards.
Before electrical work within the restricted approach boundary can proceed, an Energized
Electrical Work Permit must be completed and signed by all employees involved in the work
and their supervisor. If it is expected that a particular task will require crossing the restricted
approach boundary, the permit should be obtained prior to beginning the work.
The permit shall be reviewed with all employees involved in the work, and their supervisor, as
part of a required job briefing conducted prior to beginning the work. The job briefing shall
cover such subjects as hazards associated with the job, work procedures involved, special
precautions, energy source controls, and PPE requirements. Important information from the
job briefing shall be noted on the permit as well.
All safety requirements (procedures, equipment, PPE, etc.) indicated as necessary by the
permit must be implemented/obtained prior to beginning the work. When the work is
complete, the completed permit must be forwarded to EH&S.
An Energized Electrical Work Permit may be authorized for a recurring task if the task and
associated risks are very consistent and can be adequately described on the permit. This is
indicated on the permit by checking the “Extended Duration” checkbox. If there is any variation
in the risks associated with the recurring task, the permit must require the appropriate level
of protection for the highest level of risk (e.g. the highest voltage and highest HRC that might
be involved in completing the recurring task). Employees and supervisors should carefully
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 33
consider all possible versions of the permitted task before authorizing such a permit. A copy
of any extended duration permits must be forwarded to EH&S immediately after it is approved.
XIII. GENERAL ENERGIZED ELECTRICAL WORK RULES
Once the Energized Electrical Work Permit is completed and signed, work may begin. The
following rules must be adhered to at all times when conducting work on energized electrical
conductors or circuit parts:
Employees shall be alert for changes in the job or task that may expose them to
additional hazards that were not part of the original plan.
Employees shall not reach blindly into areas that might contain exposed energized
electrical conductors or circuit parts.
Employees shall not enter areas containing electrical hazards unless illumination is
provided that enables the employees to perform the work safely. Where lack of
illumination or an obstruction precludes observation of the work to be performed,
employees shall not perform any task within the limited approach boundary of energized
electrical conductors or circuit parts operating at 50 volts or more or where an electrical
hazard exists.
Conductive materials shall be handled in a manner that prevents accidental contact with
energized electrical conductors or parts. Long objects that are difficult to control
should be handled by two employees, one at each end.
Metal “fish lines” or fish lines with a metal “nosing” should not be used for work
associated with exposed energized electrical conductor or circuit part. Nonconductive
pulling and fishing equipment should be used.
Employees shall use protective shields, protective barriers, or insulating materials as
necessary to avoid inadvertent contact with exposed energized electrical conductor or
circuit part in enclosed or confined work spaces. If the space meets the definition of a
“confined space”, the TWU Confined Space Entry Program applies (live electrical work
in a “permit-required” confined space will require both a confined space entry permit
and an energized electrical work permit).
If employees may be exposed to hazards from equipment or systems adjacent to the
area where the live work is being conducted, the adjacent equipment or systems may
need to be locked out in accordance with the TWU Lockout/Tagout program.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 34
XIV. EMPLOYEE TRAINING
In addition to the requirement for employees to receive sufficient education and training to
meet the definition of a Qualified Person above, all employees who will be unescorted within
the limited approach boundary shall receive training on the following:
Skills and techniques necessary to distinguish exposed energized electrical conductors
and circuit parts from other parts of electrical equipment,
Skills and techniques necessary to determine the nominal voltage of exposed energized
electrical conductors and circuit parts
How to determine limited and restricted approach boundaries and recognize that these
boundaries are related to protection from exposure to electrical shock and
electrocution, specified in NFPA 70E Table 130.4(D)(a) and Table 130.4(D)(b) and the
corresponding voltages to which the qualified person will be exposed
Decision-making process necessary to be able to do the following:
a. Perform the job safety planning
b. Identify electrical hazards
c. Assess the associated risk
d. Select the appropriate risk control methods from the hierarchy of controls, including
personal protective equipment
How to select an appropriate test instrument to verify the absence of voltage, including
interpreting indications provided by the device. The training shall include information
that enables the employee to understand all limitations of each test instrument that
might be used.
Emergency procedures including how to release victims from contact with energized
electrical conductors or circuit parts, and
Requirements under this program and TWU’s Lockout/Tagout Program.
Training shall be provided through a combination of classroom training developed and provided
by EH&S, and on-the-job training provided by employee’s supervisor. Tasks that are performed
less often than once per year shall require retraining before the performance of the work
practices involved.
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 35
Classroom training and necessary on the job training shall be provided to employees prior to
conducting any work on energized conductors or circuit parts. Retraining will be conducted at
least annually and when any of the following occur:
The supervision or Lockout/Tagout periodic inspections indicate that an employee is not
complying with the safety-related work practices
New technology, new types of equipment, or changes in procedures necessitate the use
of safety-related work practices
The employee needs to review tasks that are performed less often than once per year
The employee needs to review safety-related work practices that are not normally used
by the employee during regular job duties
The employee’s job duties change
TWU shall document that each employee exposed to electrical safety risk has received the
required training and said documentation will be in accordance with the following:
Be made when the employee demonstrates proficiency in the work practices involved
Be retained for the duration of the employee’s employment
Contain the content of the training, each employee’s name, and dates of training
XV. CONTRACTORS
This section describes the responsibilities of contractors performing electrical work at TWU
facilities, as well as the responsibilities of the TWU employees overseeing those contractors.
The TWU employees responsible for bringing contractors on site must ensure that the
contractor is provided with the following:
Information about known electrical hazards related to the contractor’s work, which
might not be recognized by the contractor.
Known hazards about the installed equipment that the contractor needs to perform the
risk assessments required by NFPA 70E.
Reports of observed violations of NFPA 70E by the contractor’s employees.
The contactor shall ensure that each of their employees is instructed in the hazards
communicated to them by TWU. This will be in addition to the basic training required by NFPA
TWU Electrical Work Safety Program Revised: 12/03/2019 To ensure current version see https://twu.edu/health-safety/safety-programs/occupational-safety/electrical-work-safety/ Page 36
70E. The contractor is also responsible for ensuring compliance with NFPA 70E and the
contractor’s electrical safety program.
The contractor shall inform TWU of the following:
Any unique hazards presented by the contractor’s work.
Hazards identified during the course of work by the contract employer that were not
communicated to the contractor by TWU. This information must be communicated via
a documented meeting.
The measures the contractor took to correct any violations reported by TWU and to
prevent such violation from recurring in the future.
TWU Electrical Work Safety Program Revised: 10/30/2019 To ensure current version see: https://twu.edu/health-safety/safety-programs/electrical-safety Page 37
XVI. ATTACHMENTS
A. Attachment 1 – Energized Electrical Work Permit
Revised: 10/30/2019 To ensure current version see: https://twu.edu/health-safety/safety-programs/electrical-safety
ENERGIZED ELECTRICAL WORK PERMIT ***Return completed and approved form to EH&S for recordkeeping***
SECTION I Work Order #
Extended Duration: One time use only: Date Start: Expiration Date:
Building: Room/Area: Job Supervisor:
Description of work to be done:
Description of circuit/equipment to be worked on:
Justification for why equipment cannot be de-energized:
SECTION II Results of Shock Risk Assessment
Shock Hazard Maximum Voltage (for ANY exposed conductor/part in the work area)
Glove Voltage Rating (Inspect and air test gloves before use and check certification date)
Shock Hazard Approach Boundaries for Alternating-Current (AC) Systems (See Table 5 in the Electrical Work Safety Program for DC info)
Nominal System Voltage, Phase to Phase*
Limited Approach Boundary Restricted Approach Boundary; Includes Inadvertent Movement Adder Exposed Movable
Conductor ** Fixed Circuit Part
Less than 50V Not specified Not specified Not specified
50 to 150V 10 ft 0 in 3 ft 6 in Avoid contact
151 to 750V 10 ft 0 in 3 ft 6 in 1 ft 0 in
751 to 15kV 10 ft 0 in 5 ft 0 in 2 ft 2 in
* For single phase systems above 250V, select the range that is equal to the maximum phase-to-ground voltage multiplied by 1.732.
** Exposed movable conductors describes a condition in which the distance between the conductor and a person is not under the control of the person. The term is normally applied to overhead line conductors supported by poles.
Limited Approach Boundary ft. Restricted Approach Boundary ft.
SECTION III Required PPE
Arc Flash PPE Category (circle): 1 2 3 4 Flash Protection Boundary ft.
Check boxes below to confirm the required items have been obtained and will be used during the live electrical work. Non-melting undergarments are always required. PPE listed below assumes that entire body will be within the arc protection boundary. If this is not the case, arc-rated PPE must cover the parts of the body within the arc protection boundary. Safety glasses and hearing protectors are always required when conducting live electrical work.
Required for PPE Category 1 (minimum arc rating for PPE: 4 cal/cm2)
Hard hat Safety glasses Hearing protection Heavy-duty leather gloves Leather footwear [AND]
Arc-rated shirt (long sleeve) and pants [OR] Arc-rated coverall [AND]
Arc-rated face shield [OR] Arc flash suit hood
Revised: 10/30/2019 To ensure current version see: https://twu.edu/health-safety/safety-programs/electrical-safety
Required for PPE Category 2 (minimum arc rating for PPE: 8 cal/cm2)
Hard hat Safety glasses Hearing protection Heavy-duty leather gloves Leather footwear [AND]
Arc-rated shirt (long sleeve) and pants [OR] Arc-rated coverall [AND]
Arc-rated face shield and arc-rated balaclava [OR] Arc-rated flash suit hood
Required for PPE Category 3 (minimum arc rating for PPE: 25 cal/cm2)
Hard hat Safety glasses/goggles Hearing protection Arc-rated gloves Leather footwear [AND]
Arc-rated shirt (long sleeve) and pants [OR] Arc-rated coverall [OR] Arc-rated flash suit (jacket/pants/hood)
Required for PPE Category 4 (minimum arc rating for PPE: 40 cal/cm2)
STOP! THINK! RE-EVALUATE FEASIBILITY OF LOCKOUT.
Hard hat Safety glasses/goggles Hearing protection Arc-rated gloves Leather footwear [AND]
Arc-rated shirt (long sleeve) and pants [OR] Arc-rated coverall [OR] Arc-rated flash suit (jacket/pants/hood)
LIVE ELECTRICAL WORK MAY NOT PROCEED IF THE INCIDENT ENERGY IS >40 cal/cm2 OR PPE CATEGORY IS >4!
SECTION IV Mandatory Requirements For All Permits (check off when completed)
Necessary insulated/voltage-rated tools, covers, shields, and testing equipment is available.
Attendant worker must be able to cut off all power sources in the event of an emergency and have emergency communication equipment (i.e. radio, cell phone). Attendant worker is not permitted to assist in electrical work.
All workers, including Attendant, must be appropriately trained, qualified, and have full knowledge of equipment.
Set up barriers (caution tape/barricades) at the limited approach or arc flash boundary (whichever is farther out).
Remove all metal apparel that may cross restricted approach boundary or otherwise present an electrical contact hazard (rings, watches, necklaces, metal frame glasses).
Job briefing including discussion of any job specific hazards (describe hazards below):
Additional Safety Requirements (check off when completed, if required for this work task)
Non-conductive head wear (i.e. Class E hard hat), required if there is a potential for head contact at any voltage.
Dielectric overshoes (required if there is a step and touch shock potential).
Check here if any additional information is added to this work permit such as special requirements, procedures, or written work plans (examples include lockout procedures for adjacent equipment and confined space entry permits).
SECTION V
Approvals to Perform the Work while Electrically Energized
This permit is not approved unless signed by the employees conducting the work and their supervisor. Signature of workers verifies that they are a properly trained Qualified Person who is informed of all relevant hazards
Supervisor
Attendant
Worker
Worker
Worker
Worker
Worker
Worker